JP2017208980A - Failure diagnosis system, and failure diagnosis method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a failure diagnosis system and a failure diagnosis method that can identify a failure solar battery module with ease without removing the solar battery module from a solar battery string.SOLUTION: A failure diagnosis system comprises: a voltage monitoring unit that monitors a power generation voltage of a predetermined solar battery module in a solar battery string in which a plurality of solar battery modules are connected in series; a voltage acquisition unit that acquires voltage information indicating the power generation voltage of the predetermined solar battery module monitored by the voltage monitoring unit when power generation in the plurality of solar battery modules is selectively prevented; and a determination unit that determines the failure solar battery module on the basis of the voltage information acquired by the voltage acquisition unit.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a failure diagnosis system and a failure diagnosis method.

  In order to monitor the failure of solar panels in solar power generation facilities, the introduction of string monitoring devices is progressing. This is a device that detects a failure for each string in which a dozen or so photovoltaic modules (hereinafter also referred to as PV modules) are connected in series.

  For example, consider a case where one PV module fails in a 1 megasite-scale solar power plant. In one megasite, for example, about 4000 PV modules are used, and it takes a lot of labor and time to find one faulty module out of 4000.

  In this regard, by introducing the above-described string monitoring device, it is possible to specify a failed PV module up to a string unit. When a problematic string is identified, it is known to use a device called an IV characteristic measuring device in order to identify one failed PV module (for example, Patent Document 1).

Japanese Patent No. 2747542

  The IV characteristic measuring instrument is a device that measures the voltage across the PV module and the current flowing through the PV module. When using the IV characteristic measuring device, the PV module is disconnected from the power conditioner (PCS), and this measuring device is connected for measurement. Thus, since one PV module is removed one by one and the IV characteristic is measured, the number of work steps is large and time-consuming. There may also be work mistakes (including poor connections) when reconnecting PV modules. Further, the PV module cannot generate power during the measurement of the IV characteristics.

  Accordingly, an object of the present invention is to provide a failure diagnosis system and a failure diagnosis method that can easily identify a failed PV module without removing the PV module.

  A failure diagnosis system according to one aspect of the present invention includes a voltage monitoring unit that monitors a power generation voltage of a predetermined solar cell module in a solar cell string in which a plurality of solar cell modules are connected in series, and the plurality of solar cell modules A voltage acquisition unit that acquires voltage information indicating a power generation voltage of the predetermined solar cell module monitored by the voltage monitoring unit while selectively preventing power generation in the voltage information acquired by the voltage acquisition unit And a determination unit that determines a failed solar cell module.

  In addition, the problems disclosed by the present application and the solutions thereof will be clarified by the description in the column of the embodiment for carrying out the invention and the description of the drawings.

  According to the present invention, a failed PV module can be easily identified without removing the PV module.

It is the schematic which shows an example of the solar energy power generation system with which the failure diagnosis system which concerns on 1st and 2nd embodiment is applied. It is a figure explaining the change of the voltage of each solar cell module in the state which one solar cell string contained in the photovoltaic power generation system of FIG. 1 is operating normally, and the state where abnormality occurred. It is a graph which shows an example of the IV characteristic of a solar cell module. It is a figure explaining the principle which identifies the solar cell module which failed in 1st and 2nd embodiment. It is a figure explaining the voltage change of each solar cell module in the case where the solar cell module which failed in 1st and 2nd embodiment is shielded, and the case where a normal solar cell module is shielded. 1 is a schematic diagram of a failure diagnosis system according to a first embodiment. It is a figure which shows an example of the circuit structure of the solar cell module which comprises the solar energy power generation system of FIG. It is a figure which shows an example of the method of shielding a solar cell module in 1st Embodiment. It is a block diagram which shows the circuit structure of the string monitoring unit (SSU) in 1st Embodiment. 1 is a block diagram illustrating a failure diagnosis system according to a first embodiment. It is a figure which shows an example of the voltage value of the shielded solar cell module and corresponding string monitoring unit (SSU) memorize | stored in a memory | storage part. It is a flowchart which shows an example of the failure diagnosis procedure in 1st Embodiment. It is a flowchart which shows the other example of the failure diagnosis procedure in 1st Embodiment. It is the schematic of the failure diagnosis system which concerns on 2nd Embodiment. It is a block diagram which shows the failure diagnosis system which concerns on 2nd Embodiment. It is a figure which shows an example of the deviation from the voltage value of the shielded row | line | column or column memorize | stored in a memory | storage part, and a corresponding string monitoring unit (SSU), and the voltage before shielding. It is a flowchart which shows an example of the failure diagnosis procedure in 2nd Embodiment. It is a figure which shows the modification of 1st and 2nd embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings as appropriate. In the drawings, the same or similar components are denoted by the same or similar reference numerals.

[Solar power generation system to which failure diagnosis system is applied]
With reference to FIGS. 1-3, an example of the solar power generation system to which the failure diagnosis system according to the first and second embodiments is applied will be described.

  As shown in FIG. 1, the photovoltaic power generation system 60 includes a power conditioner (hereinafter referred to as PCS) 61, a plurality of solar cell strings 71 to 74, and a plurality of connection boxes 91 and 92. The A plurality of connection boxes 91 and 92 are connected in parallel to the PCS 61, and a plurality of solar cell strings 71 to 74 are connected in parallel to one connection box 92.

  The solar cell strings 71 to 74 are configured to include a plurality of solar cell modules connected in series. In addition, string monitoring units (hereinafter referred to as SSUs) 81 to 84 are attached to the solar cell strings 71 to 74, respectively. The SSUs 81 to 84 monitor the generated voltage of the specific solar cell modules 71 to 74 and transmit voltage information indicating the generated voltage to the management unit (hereinafter referred to as MU) 62, for example, wirelessly. The SSUs 81 to 84 can also monitor currents flowing through the solar cell strings 71 to 74 and transmit current information indicating the currents to the MU 62.

  Here, the solar cell strings 71 to 74 may be collectively referred to as the solar cell string 70. Further, the SSUs 81 to 84 may be collectively referred to as the SSU 80. In addition, the connection boxes 91 and 92 may be collectively referred to as the connection box 90.

  Consider the operation of one solar cell string 70 in such a photovoltaic power generation system 60. Here, for convenience of explanation, as shown in FIG. 2, one solar cell string 70 includes five solar cell modules PV1 to PV5 connected in series, and has an output voltage of 100 V as a whole. . Further, it is assumed that the SSU 80 is attached to the fourth solar cell module PV4 from the upstream side.

  The individual solar cell modules PV1 to PV5 included in the solar cell string 70 generate power at a power generation voltage of 20 V as shown in FIG. At this time, the SSU 80 outputs voltage information of 20V indicating the power generation voltage of the solar cell module PV4. In addition, the SSU 80 may output current information indicating the current flowing through the solar cell string 70.

  On the other hand, for example, as shown in FIG. 2B, in the state where the solar cell module PV2 is out of order, the remaining solar cell modules PV1, PV3 to PV5 each generate power with a generated voltage of 25V.

  Specifically, for example, when the solar cell module PV2 stops power generation due to a failure, the output voltage of the solar cell string 70 decreases from 100V to 80V, and no current flows through the solar cell string 70. Here, as shown in FIG. 3, it is known that the output voltage of the solar cell module increases when the current flowing through the solar cell module decreases from the short-circuit current Isc, and finally reaches the open circuit voltage Voc. Due to the IV characteristics of such a solar cell module, when no current flows through the solar cell string 70, the output voltages of the normal solar cell modules PV1, PV3 to PV5 increase. Then, when the output voltage of each of the solar cell modules PV1, PV3 to PV5 reaches 25V, that is, when the output voltage of the entire solar cell string 70 returns to 100V, the current starts to flow again through the solar cell string 70. In addition, about the solar cell module PV2 which failed, an electric current will flow through the bypass diodes D1-D3 mentioned later (refer FIG. 7).

  At this time, when a failure occurs in the solar cell module to which the SSU 80 is not attached as shown in FIG. 2B, the SSU 80 outputs voltage information indicating the generated voltage 25V of the solar cell module PV4. Moreover, when the failure has occurred in the solar cell module itself to which the SSU 80 is attached as shown in FIG. 2C, the voltage information output by the SSU 80 is zero. Thus, when any of the solar cell modules PV1 to PV5 included in the solar cell string 70 fails, the voltage value indicated by the voltage information output from the SSU 80 varies.

  The SSU 80 may output current information indicating the current flowing through the solar cell string 70. Since the power generated in each of the normal solar cell modules PV1, PV3 to PV5 is constant, the current value indicated by the current information described above is the power generation of the remaining solar cell modules due to the failure of a specific solar cell module. It will decrease with increasing voltage.

[Principle of fault diagnosis]
Based on the operation of the solar cell string 70 described above, the principle of finding a failure of the solar cell module in the first and second embodiments will be described with reference to FIGS. 4 and 5. Here, as in FIGS. 2A and 2B, it is assumed that the solar cell string 70 is composed of five solar cell modules PV1 to PV5, and the solar cell module PV2 is out of order. The following description focuses on failure diagnosis based on voltage information.

  As shown in FIG. 4, power generation of each solar cell module is prevented by covering the light receiving surfaces of the solar cell modules PV <b> 1 to PV <b> 5 with the shield 40 while moving the plate-like shield 40. For example, as shown in FIG. 5A, when the normally functioning solar cell module PV1 is shielded by the shield 40, the power generation of the solar cell module PV1 is hindered. As a result, the solar cell modules PV <b> 3 to PV <b> 5 each generate a power generation voltage of 33 V in order to cover the output voltage 100 V of the entire solar cell string 70 with only three normal solar cell modules PV <b> 3 to PV <b> 5. Therefore, the SSU 80 transmits the voltage value 33V to the MU 62 as voltage information. The voltage value 33V is greater than the voltage value 25V indicated by the voltage information when any of the solar cell modules PV1 to PV5 described in relation to FIG.

  Further, for example, as shown in FIG. 5 (b), even if the failed solar cell module PV2 is shielded by the shield 40, the other solar cell modules PV1, PV3 to PV5 are not affected. Therefore, these normal solar cell modules PV1 and PV3 to PV5 each output the generated voltage 25V, as in the case of FIG. The SSU 80 transmits the voltage value 25V to the MU 62 as voltage information. That is, the voltage value indicated by the voltage information in this case is equal to the voltage value 25V indicated by the voltage information when an abnormality occurs in any of the solar cell modules PV1 to PV5 described in relation to FIG. .

Thus, the voltage value indicated by the voltage information output from the SSU 80 when the solar cell module PV2 in which an abnormality such as a failure occurs is shielded shields one of the normal solar cell modules PV1, PV3 to PV5. Sometimes it becomes relatively smaller than the voltage value indicated by the voltage information output from the SSU 80.
In addition, when the solar cell module PV2 in which an abnormality has occurred is shielded, the amount of change in the generated voltage (25V-25V = 0V) indicated by the voltage information before and after power generation is hindered is normal solar cell modules PV1, PV3. It is relatively small compared to the amount of change in the generated voltage (33V-25V = 8V) when any of PV5 is shielded.
In addition, when the solar cell module PV2 itself to which the SSU 80 is attached is broken as shown in FIG. 5C, the voltage information indicates a low power generation voltage before the solar cell module is shut off, so that the shutoff is performed. The solar cell module PV2 can be determined as a failure from before.

  Such a relationship is the same even when abnormality occurs in a plurality of solar cell modules included in the solar cell string 70. For example, it is assumed that the solar cell modules PV1 and PV2 have failed. In this case, if any of the normal solar battery modules PV3 and PV5 is shielded, the voltage information output from the SSU 80 indicates a voltage value of 50V. Further, when any one of the solar cell modules PV1 and PV2 is shielded, the voltage information output from the SSU 80 shows a voltage value 33V smaller than the voltage value 50V when the normal solar cell module is shielded.

Thus, the voltage value indicated by the voltage information when the solar cell module in which an abnormality has occurred is shielded is relatively smaller than the voltage value indicated by the voltage information when the normal solar cell module is shielded. . Using this fact, it can be determined that the shielding solar cell module is broken when the voltage information indicates a relatively small generated voltage.
In addition, when a solar cell module in which an abnormality has occurred is shielded, the amount of change in the generated voltage indicated by the voltage information before and after power generation is hindered is compared to the amount of change in the generated voltage when a normal solar cell module is shielded. Is relatively small. Using this fact, it can be determined that the shielding solar cell module is broken when the amount of change in the generated voltage is relatively small.

  It is also possible to perform failure diagnosis based on the current value of the solar cell string 70. In this case, the current information when the abnormal solar cell module is shielded shows a relatively large current value as compared with the current information when the normal solar cell module is shielded. In addition, when the solar cell module in which an abnormality has occurred is shielded, the amount of change in current indicated by the current information before and after the generation of power is hindered is compared to the amount of change in current when the normal solar cell module is shielded. Relatively small. An advantage of failure diagnosis based on current information is that even when a solar cell module to which the SSU 80 is attached fails, it can be determined whether other solar cell modules included in the solar cell string 70 have failed.

  It is also possible to perform failure diagnosis based on both voltage information and current information. In this case, it is expected that the accuracy of diagnosis is improved.

[First Embodiment]
Based on the principle of failure diagnosis described above, the failure diagnosis system according to the first embodiment will be described with reference to FIGS. Here, it is assumed that the solar cell module P5 is broken as shown in FIG. 6, but other solar cell modules may be broken, or a plurality of solar cell modules may be broken.

<Configuration of fault diagnosis system>
As shown in FIG. 6, the failure diagnosis system 1 includes a shield 40, an SSU 10, a dummy SSU 20, and a failure diagnosis device 30. Hereinafter, each component of the failure diagnosis system 1 will be described in order.

  The shield 40 is a plate-like member, and shields the light receiving surfaces of the plurality of solar cell modules so that power generation in each of the plurality of solar cell modules is hindered. For example, when the solar cell string 70 includes the solar cell modules P1 to P12 as shown in FIG. 6, the shield 40 shields the solar cell modules one by one. The shield 40 is provided with an arm 41 for appropriately arranging the shield 40 on a desired solar cell module. The arm 41 is driven by a motor (drive means) (not shown) based on an instruction from the failure diagnosis device 30, for example. The arm 41 can also move in the order of the solar cell modules P1 to P12 as shown by, for example, an alternate long and short dash line in FIG. 6, for example, solar cell modules P1, P8, P9, P10, P7, P2, P3, P6, P11, It can also be moved in other orders such as P12, P5, P4.

  In order to prevent power generation in each of the solar cell modules P1 to P12, the shield 40 may cover the entire light receiving surface of the corresponding solar cell module, or may partially cover the light receiving surface of the corresponding solar cell module. It may be covered.

  For example, as shown in FIG. 7, a case is considered in which one solar battery module M is configured of solar cells connected in series and arranged in 6 rows and 7 columns. That is, the solar cell module M includes six stages of solar cells that are folded back in units of seven. The two-stage solar cells form one cluster. Therefore, the solar cell module M includes clusters 1 to 3 connected in series.

In the solar cell module M, a bypass circuit is formed in parallel with three clusters between an input terminal (minus terminal) and an output terminal (plus terminal). In the bypass circuit, bypass diodes D1 to D3 are provided in series.
A connection point C3 between the clusters 1 and 2 and a connection point C1 between the bypass diode D1 and the bypass diode D2 are connected. Further, the connection point C4 between the clusters 2 and 3 and the connection point C2 between the bypass diode D2 and the bypass diode D3 are connected.

  Therefore, when each of the clusters 1 to 3 is functioning normally, the current I flowing into the input terminal of the solar cell module M is output from the output terminal via the clusters 1 to 3. At this time, since none of the bypass diodes D1 to D3 conducts, no current flows in the bypass circuit.

  For example, when cluster 1 fails, no current flows through cluster 1. At this time, the bypass diode D1 becomes conductive, and the current I flows through the normal clusters 2 and 3 bypassing the cluster 1. In this way, even when all or a part of the solar cell module M fails, a current can be passed through the solar cell string 70 via the bypass circuit, and power is generated in the normal solar cell module M or a normal cluster. It is possible to effectively extract the power.

  In the solar cell module M having such a bypass circuit, the shield 40 may be disposed so as to prevent power generation in all the clusters 1 to 3. That is, for example, as shown in FIG. 8, the shielding object 40 is arranged across the light receiving surfaces of the clusters 1 to 3.

  The SSU 10 monitors the power generation voltage of a predetermined solar cell module in the solar cell string 70 and also monitors the current flowing through the solar cell string 70. The SSU 10 functions as a voltage monitoring unit and a current monitoring unit. As shown in FIG. 9, the SSU 10 includes a voltage detection circuit 11, a current detection circuit 12, an A / D conversion circuit 13, an arithmetic circuit 14, a broadband unit (BB unit) 15, an RF unit 16, and an antenna 17. The SSU 10 has four terminals 18a, 18b, 19a, and 19b.

  The terminal 18a is connected to the output terminal of the upstream solar cell module, and the terminal 18b is connected to the input terminal of the solar cell module to be monitored. The current flowing through the wires connecting the terminals 18a and 18b corresponds to the current flowing through the solar cell string 70, and the current detection circuit 12 is provided to detect such current.

  Moreover, the terminal 19a is connected to the output terminal of the solar cell module to be monitored. The voltage between the terminal 18b and the terminal 19a corresponds to the power generation voltage of the solar cell module to be monitored, and the voltage detection circuit 11 is provided to detect such voltage.

  The analog signals indicating the voltage value and the current value detected by the voltage detection circuit 11 and the current detection circuit 12 are converted into digital signals by the A / D conversion circuit 13 and output to the arithmetic circuit 14. The voltage information and current information converted into the digital signal and the calculation result in the calculation circuit 14 are transmitted from the antenna 17 to the MU 62 via the BB unit 15 and the FR unit 16.

  The dummy SSU 20 is a receiver that can receive voltage information and current information transmitted from the SSU 10 toward the MU 62. The dummy SSU 20 is connected to the failure diagnosis device 30 via, for example, a USB, and outputs the received voltage information and current information to the failure diagnosis device 30. The dummy SSU 20 may be built in the failure diagnosis apparatus 30.

  The failure diagnosis device 30 is a device that performs failure diagnosis based on voltage information or current information acquired from the dummy SSU 20. The failure diagnosis apparatus 30 may be a portable information device such as a tablet terminal, a notebook computer, or a smartphone so as to be suitable for the user to carry. Such a failure diagnosis apparatus 30 includes an acquisition unit 31, a determination unit 32, a storage unit 33, a display unit 34, and an input unit 35 as shown in FIG. Hereinafter, each of these functional units will be described in order.

  The acquisition unit 31 functions as a voltage acquisition unit that acquires voltage information indicating the power generation voltage of a predetermined solar cell module monitored by the SSU 10. Specifically, the acquisition unit 31 acquires voltage information when the power generation in each of the plurality of solar cell modules is blocked and voltage information before the power generation is blocked.

As a specific example, for example, the SSU 10 illustrated in FIG. 6 stores 9.1 V in the storage unit 32 as the voltage value before shielding.
Next, when each of the solar cell modules P1 to P12 included in the solar cell string 70 is shielded, the acquisition unit 31 obtains 10.0 V from the SSU 10 as the voltage value of the SSU 10 corresponding to the solar cell modules P1 to P3 and P6 to P12. Is acquired as 0.0V as the voltage value of the SSU 10 corresponding to the solar cell module P4 and 9.1V as the voltage value of the SSU 10 corresponding to the solar cell module P5 (see FIG. 11).

The acquisition unit 31 can also function as a current acquisition unit that acquires current information monitored by the SSU 10 and indicating the current flowing through the solar cell string 70. Specifically, the acquisition unit 31 may acquire current information when power generation is prevented in each of the plurality of solar cell modules and current information before power generation is prevented.
The acquisition unit 31 stores the acquired voltage information and current information in the storage unit.

The determination unit 32 determines the failed solar cell module based on the voltage information acquired by the acquisition unit 31. For example, the determination unit 32 may determine a solar cell module in which power generation is hindered when the voltage information indicates a relatively low power generation voltage as a failed solar cell module.
As a specific example, the voltage of the SSU 10 before shielding is first determined, and when this voltage is very lower than the reference voltage of the solar cell module, the solar cell module to which the SSU 10 is attached is first determined to be a failure. The solar cell module reference voltage at this time can be determined according to the specifications of the solar cell module. In the example of FIG. 11, it is about 8.3V, for example. Next, when the solar cell module to which the SSU 10 is attached is not out of order, the determination is made based on the result of shielding each of the solar cell modules P1 to P12 included in the solar cell string 70 shown in FIG. In this case, as described above, the voltage value 9.1V of the SSU 10 corresponding to the solar cell module P5 is relatively lower than 10.0V as the voltage value of the SSU 10 corresponding to the solar cell modules P1 to P3 and P6 to P12. Therefore, the determination part 32 determines with the solar cell module P5 having failed.

  The determination unit 32 may determine, as a failed solar cell module, a solar cell module in which the amount of change in the generated voltage indicated by the voltage information is relatively small before and after power generation is hindered. As a specific example, in the solar cell string 70 shown in FIG. 6, the voltage value of the SSU 10 shows 9.1 V before shielding, whereas the solar cell modules P1 to P3 and P6 to P12 are shielded. The voltage value is 10.0V, and the voltage value of the SSU 10 is 9.1V when the solar cell module P5 is shielded. That is, before and after shielding, the voltage value of the SSU 10 corresponding to the solar cell modules P1 to P3 and P6 to P12 increases by 0.9 V, and the voltage value of the SSU 10 corresponding to the solar cell module P5 does not change. Therefore, the determination part 32 determines with the solar cell module P5 having failed.

  Alternatively, the determination unit 32 may determine a failed solar cell module based on the current information acquired by the acquisition unit 31. For example, the determination unit 32 may determine a solar cell module in which power generation is hindered when the current information indicates a relatively high current as a failed solar cell module. In addition, the determination unit 32 may determine a solar cell module in which the amount of change in current indicated by current information is relatively small before and after power generation is prevented as a failed solar cell module.

  The determination unit 32 displays the determination result on the display unit 34 and stores it in the storage unit 33.

  The memory | storage part 33 matches and memorize | stores the solar cell module with which electric power generation is prevented, and voltage information. For example, when the solar cell modules P1 to P12 included in the solar cell string 70 shown in FIG. 6 are shielded in order, the storage unit 33 stores the SSU 10 corresponding to the solar cell modules P1 to P3 and P6 to P12 as shown in FIG. Is stored as 10.0 V, 0.0 V is stored as the voltage value of the SSU 10 corresponding to the solar cell module P4, and 9.1 V is stored as the voltage value of the SSU 10 corresponding to the solar cell module P5.

  The storage unit 33 may also store a solar cell module in which power generation is prevented and current information in association with each other.

  The storage unit 33 may store voltage information and current information before shielding, a determination result in the determination unit 32, and a program for executing each function of the failure diagnosis apparatus 30.

  The display unit 34 displays the determination result in the determination unit 32. For the user, the display unit 34 displays, for example, a failure diagnosis “start button”, “end button”, voltage value or current value “record button”, and the number of the corresponding solar cell module.

  The input unit 35 is an interface with the user, and is configured with, for example, a touch panel. The input unit 35 outputs a signal corresponding to the “start button”, “end button”, and “record button” pressed by the user to the determination unit 32.

<Failure diagnosis procedure>
A procedure for performing failure diagnosis of the solar cell string 70 using the failure diagnosis system 1 having the above-described configuration will be described. The failure diagnosis may be performed based on the voltage information as described above, or may be performed based on the current information. Hereinafter, a specific example of a procedure for performing a failure diagnosis based on a relative comparison between voltage information and current information will be described.

(Failure diagnosis based on voltage information)
With reference to FIG. 12, an example of a failure diagnosis procedure based on voltage information will be described.
First, in step S01, a voltage value before shielding is stored in the storage unit (memory) 33. Next, in step S02, the voltage value is compared with the reference voltage. If the voltage value is lower than the reference voltage, the solar cell module number in which the SSU 10 is installed is displayed as a failure in step S03. If the solar cell module in which the SSU 10 is installed is not in failure, it is determined in step S11 whether or not the user has pressed (ON) the “start button” on the display screen of the failure diagnosis apparatus 30. If it is determined that the user has not pressed the “start button”, the process is executed again from step S01.

  If it is determined that the user has pressed the “start button”, “1” is set as the number of the solar cell module to be shielded in step S12. At this time, the shielding object 40 is arranged so that the solar cell module corresponding to the number “1” (for example, the solar cell module P1 in FIG. 6) is shielded.

  Next, in step S <b> 13, it is determined whether or not the user has pressed an “end button” on the display screen of the failure diagnosis apparatus 30. If it is determined that the “end button” has not been pressed, the acquisition unit 31 acquires voltage information from the SSU 10 via the dummy SSU 20 in step S14.

  Next, in step S <b> 15, it is determined whether or not the user has pressed a “record button” on the display screen of the failure diagnosis apparatus 30. If it is determined that the “record button” has not been pressed, the process returns to step S14 to acquire the voltage value from the SSU 10 again. On the other hand, if it is determined that the “record button” is pressed (ON), the voltage value indicated by the voltage information is stored in the storage unit (memory) 33 in association with the shielded solar cell module in step S16.

  Thereafter, in step S17, “+1” is added to the number of the solar cell module to be shielded, and the process returns to step S13. At this time, the shield 40 is disposed on the solar cell module to be shielded next (for example, the solar cell module P2 in FIG. 6).

  When it is determined in step S13 that the “end button” is pressed (ON), in step S18, the determination unit 32 corresponds to a relatively low voltage value among the voltage values stored in the storage unit 33. The number of the solar cell module is extracted.

  Next, in step S19, the determination unit 32 causes the display unit 34 to display the solar cell module number extracted in the previous procedure as a failed solar cell module. In this way, a series of fault diagnosis procedures based on the voltage information is completed.

  In addition, before checking all the solar cell modules included in the solar cell string 70 to be diagnosed, when the user presses the “end button” in step S13, the voltage value stored in the storage unit 33 until then is set. A failure diagnosis is performed based on this. Since it is possible that the location of the failure may be found during the diagnosis operation, it is considered that entrusting the user with how to proceed with the failure diagnosis leads to an improvement in work efficiency.

(Failure diagnosis based on current information)
With reference to FIG. 13, an example of a procedure for failure diagnosis based on current information will be described.
The diagnostic procedure described here is substantially the same as the diagnostic procedure described in connection with FIG. That is, the solar cell modules are individually shielded, the current value at that time is recorded (steps S24 to S27), and the failed solar cell module is identified by comparing the recorded current values (step S28). , S29). However, in the failure diagnosis based on the current information, it is determined that the solar cell module corresponding to the relatively high current value has failed.

<Effects of First Embodiment>
According to the first embodiment, failure diagnosis can be performed in a state where the solar cell modules included in the solar cell string 70 are connected to each other. And since the faulty solar cell module can be specified easily, it suffices to replace only the solar cell module determined to be faulty.

  Therefore, the work is simplified and shortened compared to the method of performing fault diagnosis using an IV characteristic measuring device after disconnecting the solar cell modules from each other, and further, for example, a work mistake in reconnection occurs. I don't get it. Moreover, failure diagnosis can be performed while generating power.

[Second Embodiment]
The failure diagnosis system 2 according to the second embodiment will be described with reference to FIGS. Here, the solar cell string 70 is formed such that a plurality of solar cell modules are arranged in 3 rows and 4 columns. However, the solar cell string 70 may be formed such that a plurality of solar cell modules are arranged in m rows (m is an integer of 2 or more) × n columns (n is an integer of 3 or more).
Moreover, although the solar cell module P6 shall be out of order like FIG. 14, the other solar cell module may be out of order and the several solar cell module may be out of order.

<Configuration of fault diagnosis system>
As shown in FIG. 14, the failure diagnosis system 2 includes a shield 140, an SSU 110, a dummy SSU 120, and a failure diagnosis device 130. Since the SSU 110 and the dummy SSU 120 are the same as those in the first embodiment, description thereof is omitted.

  As shown in FIG. 14, the shielding object 140 includes a first shielding part 141 and a second shielding part 142.

The 1st shielding part 141 shields the light-receiving surface in a plurality of solar cell modules so that power generation in each row of a plurality of solar cell modules is prevented. For example, in the solar cell string 70 shown in FIG. 14, the first shielding unit 141 is a plate member that shields over the solar cell modules (for example, solar cell modules P <b> 1 to P <b> 4) constituting each row.
The first shield 141 is attached with an arm 143 that supports the first shield 141 movably across the rows of solar cell strings 70. The arm 143 is driven by a motor (drive means) (not shown) based on an instruction from the failure diagnosis device 130, for example. The arm 143 can move in the order of the first row to the third row, for example, as indicated by a one-dot chain line in FIG. 14, or can move in other orders, for example, the third row, the second row, and the first row. You can also.

The 2nd shielding part 142 shields the light-receiving surface in a plurality of solar cell modules so that power generation in each row of a plurality of solar cell modules is prevented. For example, in the solar cell string 70 shown in FIG. 14, the second shielding part 142 is a plate member that shields over the solar cell modules (for example, solar cell modules P1, P8, and P9) that constitute each row.
An arm 144 is attached to the second shielding portion 142 to support the second shielding portion 142 so as to be movable between the rows of solar cell strings 70. The arm 144 is driven by a motor (drive means) (not shown) based on an instruction from the failure diagnosis device 130, for example. The arm 144 can move in the order of the first row to the fourth row, for example, as indicated by the solid arrow in FIG. 14, or the other, for example, the fourth row, the third row, the second row, and the first row. You can also move in the order.

  In FIG. 14, for convenience of drawing, the first shielding portion 141 and the second shielding portion 142 are drawn so as to intersect with each other. For example, the first shielding portion 141 covers any row of the solar cell string 70. When shielding, the 2nd shielding part 142 shall be moved out of the frame of the said solar cell string 70 so that neither row | line | column of the said solar cell string 70 may be shielded. Similarly, when the second shielding part 142 shields any column of the solar cell string 70, the first shielding part 141 does not shield any row of the solar cell string 70. It is assumed that the string 70 is moved out of the frame.

  As illustrated in FIG. 15, the failure diagnosis apparatus 130 includes an acquisition unit 131, a determination unit 132, a storage unit 133, a display unit 134, and an input unit 135. Since the display unit 134 and the input unit 135 are the same as those in the first embodiment, description thereof is omitted.

  The acquisition unit 131 acquires the first voltage information as voltage information while preventing power generation in each row of the plurality of solar cell modules, and the second voltage information as voltage information while preventing power generation in each column of the plurality of solar cell modules. get.

As a specific example, the acquisition unit 131 first acquires a voltage value (pre-shielding voltage) from the SSU 110 before shielding the solar cell module. In the example of FIG. 14, the pre-shielding voltage is 9.1V.
Next, for example, when each row of the solar cell string 70 illustrated in FIG. 14 is shielded by the first shielding unit 141, the acquisition unit 131 starts from the SSU 110 with a voltage value 0 of the SSU 110 corresponding to the first row (solar cell modules P1 to P4). 0.0V, the voltage value 12.5V of the SSU 110 corresponding to the second row (solar cell modules P5 to P8), the voltage value 14.3V of the SSU 110 corresponding to the third row (solar cell modules P9 to P12), You will get each. Further, when each column of the solar cell string 70 shown in FIG. 14 is shielded by the second shielding unit 142, the acquisition unit 131 starts from the SSU 110 with the first column (solar cell modules P1, P8, P9) and the second column (solar The voltage value 12.5V of the SSU 110 corresponding to the battery modules P2, P7, P10), the voltage value 11.1V of the SSU 110 corresponding to the third column (solar cell modules P3, P6, P11), and the fourth column (solar The voltage value 0.0V of the SSU 110 corresponding to the battery modules P4, P5, P12) is acquired (see FIG. 16).

Alternatively, the acquisition unit 131 acquires the first current information as current information while preventing power generation in each row of the plurality of solar cell modules, and the second current as current information while preventing power generation in each column of the plurality of solar cell modules. Information may be acquired.
The acquisition unit 131 stores the acquired voltage information and current information in the storage unit 133.

  The determination unit 132 has a row of the solar cell module in which the change amount of the generated voltage indicated by the first voltage information is the smallest before and after the power generation is prevented, and a change amount of the generated voltage indicated by the second voltage information before and after the generation is inhibited. The solar cell module at the position where the row of the smallest solar cell modules intersects is determined as a failed solar cell module.

  The solar cell string 70 shown in FIG. 14 will be specifically described as an example. Before the shielding, the voltage value of the SSU 110 is 9.1V, whereas when the first row is shielded, the voltage value of the SSU 110 is 0.0V, and when the second row is shielded, the voltage value of the SSU 110 is 12.5V. When the third row is shielded, the voltage value of the SSU 110 is 14.3V. Therefore, before and after shielding, the voltage value of the SSU 110 corresponding to the first row decreases by 9.1 V, the voltage value of the SSU 110 corresponding to the second row increases by 3.4 V, and the voltage of the SSU 110 corresponding to the third row. The value increases by 5.2V. For this reason, the amount of change in the generated voltage before and after shielding is the smallest in the second row.

  The voltage value of the SSU 110 is 12.5 V when the first and second rows are shielded, the voltage value of the SSU 110 is 11.1 V when the third row is shielded, and the voltage value of the SSU 110 is 0 when the fourth row is shielded. .0V is shown respectively. Therefore, before and after shielding, the voltage value of the SSU 110 corresponding to the first column and the second column increases by 3.4 V, the voltage value of the SSU 110 corresponding to the third column increases by 2.0 V, and corresponds to the fourth column. The voltage value of the SSU 110 to be lowered is 9.1V. From this, the amount of change in the generated voltage before and after shielding is the smallest in the third column.

  Therefore, the determination unit 32 determines that the solar cell module P6 at the position where the second row and the third column intersect has failed. Then, the determination unit 132 stores the solar cell module P6 in the storage unit 133.

  The storage unit 133 stores a plurality of solar cell module rows in which power generation is prevented, the first voltage information, and the absolute value of the deviation from the pre-shielding voltage of the first voltage information in association with each other. The row | line | column of the several solar cell module blocked, 2nd voltage information, and the absolute value of the deviation from the voltage before shielding of 2nd voltage information are matched and memorize | stored. For example, when each row and each column of the solar cell string 70 shown in FIG. 14 are shielded in order, the storage unit 133 has an absolute value 9.1 V of the voltage deviation of the SSU 110 corresponding to the first row, as shown in FIG. The absolute value of the voltage deviation of the SSU 110 corresponding to the second row is 3.4 V, the absolute value of the voltage deviation of the SSU 110 corresponding to the third row is 5.2 V, and the voltage deviation corresponding to the first column and the second column. , The absolute value 2.0V of the voltage deviation of the SSU 110 corresponding to the third column, and the absolute value 9.1V of the voltage deviation of the SSU 110 corresponding to the fourth column are respectively stored.

<Failure diagnosis procedure>
With reference to FIG. 17, the failure diagnosis method according to the second embodiment will be described. Here, a failure diagnosis method using voltage information is taken as an example, but diagnosis using current information is also possible.

  The failure diagnosis procedure in the second embodiment includes a voltage value acquisition procedure corresponding to shielding for each column of the solar battery string 70 (steps S32 to S37) and a voltage value acquisition procedure corresponding to shielding for each row (step S38). To S43) and a determination procedure based on the acquired voltage value (steps S44 to S46). Details will be described below.

  First, in step S30, the voltage value before blocking is stored in the storage unit (memory) 33 as the pre-shielding voltage. In step S31, it is determined whether or not the user has pressed (ON) the “start button” on the display screen of the failure diagnosis apparatus 130. If it is determined that the user has not pressed the “start button”, step S30 is executed again.

  If it is determined that the user has pressed the “start button”, “1” is set as the number of the row (vertical module) to be shielded in step S32. At this time, the first shielding portion 141 is arranged so that the solar cell modules corresponding to the column number “1” (for example, the solar cell modules P1, P8, and P9 in FIG. 14) are shielded.

  Next, in step S <b> 33, it is determined whether or not the user has pressed the “vertical end button” on the display screen of the failure diagnosis apparatus 130. If it is determined that the “vertical end button” has not been pressed, the acquisition unit 131 acquires voltage information from the SSU 110 via the dummy SSU 120 in step S34.

  Next, in step S <b> 35, it is determined whether or not the user has pressed a “record button” on the display screen of the failure diagnosis apparatus 130. If it is determined that the “record button” has not been pressed, the process returns to step S34 to acquire the voltage value from the SSU 110 again. On the other hand, if it is determined that the “record button” is pressed (ON), in step S 36, the absolute value of the value obtained by subtracting the pre-blocking voltage from the acquired voltage value is associated with the blocked column in the storage unit 133. Remembered.

  Thereafter, in step S37, “+1” is added to the number of the blocked column, and the process returns to step S33. At this time, the 1st shielding part 141 is arrange | positioned on the row | line | column (for example, solar cell module P2, P7, P10 of FIG. 14) which should be shielded next.

  When it is determined in step S33 that the “vertical end button” has been pressed (ON), the process moves to shielding the rows of solar cell strings 70 defined in and after step S38. That is, if it is determined in step S33 that the user has pressed the “vertical end button”, “1” is set as the number of the line (horizontal module) to be blocked in step S38. At this time, the 2nd shielding part 142 is arrange | positioned so that the solar cell module (for example, solar cell module P1-P4 of FIG. 14) corresponding to row number "1" may be shielded.

  Next, in step S <b> 39, it is determined whether or not the user has pressed the “lateral end button” on the display screen of the failure diagnosis apparatus 130. If it is determined that the “horizontal end button” has not been pressed, voltage information is received by the acquisition unit 131 from the SSU 110 via the dummy SSU 120 in step S40.

  Next, in step S <b> 41, it is determined whether or not the user has pressed the “record button” on the display screen of the failure diagnosis apparatus 130. If it is determined in step S41 that the “record button” has not been pressed, the process returns to step S40 to acquire the voltage value from the SSU 110 again. On the other hand, if it is determined that the “record button” is pressed (ON), the absolute value of the value obtained by subtracting the pre-blocking voltage from the acquired voltage is stored in the storage unit 133 in association with the blocked row in step S42. Is done.

  Thereafter, in step S43, “+1” is added to the number of the line to be shielded, and the process returns to step S39. At this time, the 2nd shielding part 142 is arrange | positioned on the row | line | column (for example, solar cell module P5-P8 of FIG. 14) which should be shielded next.

  If it is determined in step S39 that the “horizontal end button” has been pressed, the determination unit 132 extracts the column number corresponding to the smallest value among the absolute values recorded in the storage unit 133 in step S44. Next, in step S <b> 45, the determination unit 132 extracts the row number corresponding to the smallest value among the absolute values recorded in the storage unit 133.

  In step S46, the determination unit 132 causes the display unit 134 to display the column and row numbers extracted in the previous two procedures as the position of the failed solar cell module. In this way, a series of fault diagnosis procedures based on the voltage information is completed.

<Effects of Second Embodiment>
According to the second embodiment, in addition to being able to easily and reliably perform failure diagnosis in a state where the solar cell modules included in the solar cell string 70 are connected to each other, the voltage value (current value) is smaller than that of the first embodiment. ) Can be diagnosed with the number of acquisitions. Therefore, failure diagnosis in the large-scale photovoltaic power generation system 60 can be performed efficiently in a short time.

[Modification]
A modification of the failure diagnosis system according to the first and second embodiments will be described with reference to FIG.
In the modification, a switch is provided in the solar cell module M1 in order to prevent power generation of the target solar cell module M1.

  Specifically, as shown in FIG. 18, the switches SW1 to SW3 are attached so that the current I flowing through the solar cell string 70 flows through the bypass circuit without passing through the solar cell module M1. The switch SW1 is provided to disconnect the cluster 1 from the output terminal of the solar cell module M1. The switches SW2 and SW3 are provided to separate the clusters 2 and 3 from the bypass circuit, respectively. Therefore, by opening the switches SW1 to SW3 all at once, the solar cell module M1 is electrically disconnected from the solar cell string 70 and is in the same state as not generating power. The operation of opening and closing the switches SW1 to SW3 may be performed by an instruction from the MU 62, for example, or may be performed by a user instruction via the failure diagnosis apparatus 30 (130).

  When stopping the power generation of the solar cell module M1 for each row or column as in the second embodiment, all the solar cell modules belonging to the corresponding row or column can be opened or closed simultaneously. Good.

[Summary]
As described above, the failure diagnosis system 1 (2) includes the SSU 10 (110) that monitors the power generation voltage [current] of a predetermined solar cell module in the solar cell string 70 in which a plurality of solar cell modules are connected in series. The acquisition unit 31 (131) acquires voltage information [current] indicating the power generation voltage [current] of a predetermined solar cell module monitored by the SSU 10 (110) while selectively preventing power generation in the plurality of solar cell modules. And a determination unit 32 (132) for determining a failed solar cell module based on the voltage information [current information] acquired by the acquisition unit 31 (131).
For example, the acquisition unit 31 acquires voltage information [current information] while preventing power generation in each of the plurality of solar cell modules, and the determination unit 32 generates a power generation voltage [relative to the relatively low voltage information [current information]. The solar cell module in which power generation is hindered when the current is high may be determined as a failed solar cell module. Alternatively, the determination unit 32 replaces a solar cell module in which a change amount of the generated voltage [current] indicated by the voltage information [current information] is relatively small [relatively small] before and after power generation is hindered with a faulty solar cell module. You may determine as.
According to this embodiment, failure diagnosis can be performed in a state where the solar cell modules included in the solar cell string 70 are connected to each other. And since the faulty solar cell module can be specified easily, it suffices to replace only the solar cell module determined to be faulty. Therefore, the operation is simplified and shortened, and further, for example, an operation error in reconnection cannot occur. Moreover, failure diagnosis can be performed while generating power.

  Moreover, you may further provide the shield 40 which shields the sunlight light-receiving surface in a some solar cell module so that the electric power generation in each of a some solar cell module may be prevented. According to this embodiment, it is possible to improve the efficiency of the failure diagnosis work by automating the shielding work.

As another example, the solar cell string 70 is formed such that a plurality of solar cell modules are arranged in m rows (m is an integer of 2 or more) × n columns (n is an integer of 3 or more). The first voltage information [first current information] is acquired as the voltage information [current information] while preventing power generation in each row of the plurality of solar cell modules, and the voltage information while preventing power generation in each column of the plurality of solar cell modules. The second voltage information [second current information] is acquired as [current information], and the determination unit 132 has the largest amount of change in the generated voltage [current] indicated by the first voltage information [current information] before and after the generation is prevented. The row of small [smallest] solar cell modules and the [smallest] solar cell with the smallest amount of change in the generated voltage indicated by the second voltage information [second current information] before and after power generation is hindered And columns of modules, the solar cell module at the intersection may be determined as malfunctioning solar cell module.
According to such an embodiment, failure diagnosis can be performed with a smaller number of acquisitions of voltage value [current value]. Therefore, failure diagnosis in the large-scale photovoltaic power generation system 60 can be performed efficiently in a short time.

  Moreover, the 1st shielding part 141 which shields the sunlight light-receiving surface in a several solar cell module and the electric power generation in each row | line | column of a several solar cell module are prevented so that the electric power generation in each row | line | column of a several solar cell module is prevented. Thus, you may further provide the 2nd shielding part 142 which shields the sunlight light-receiving surface in a plurality of solar cell modules. According to this embodiment, it is possible to improve the efficiency of the failure diagnosis work by automating the shielding work.

  In addition, each of the plurality of solar battery modules M (M1) is connected in series and folded back in units of a predetermined number, and power generation of any one of the plurality of solar battery cells Bypass diodes D1 to D3 (D11 to D13) that are turned on when hindered.

As mentioned above, although embodiment of this invention was described, this invention is not limited to this. The material, shape, and arrangement of each member described above are merely embodiments for carrying out the present invention, and various changes can be made without departing from the spirit of the invention.
For example, in the first and second embodiments, the shield is moved by an arm driven by a motor, but the shield may be manually moved by an operator to shield the solar cell module.

10,110 String monitoring unit (SSU)
20,120 Dummy SSU
30, 130 Failure diagnosis device 31 Acquisition unit 32 Determination unit 33 Storage unit 40, 140 Shield

Claims (19)

A voltage monitoring unit that monitors a power generation voltage of a predetermined solar cell module in a solar cell string in which a plurality of solar cell modules are connected in series;
A voltage acquisition unit that acquires voltage information indicating a power generation voltage of the predetermined solar cell module monitored by the voltage monitoring unit when the power generation in the plurality of solar cell modules is selectively prevented;
A determination unit that determines a failed solar cell module based on the voltage information acquired by the voltage acquisition unit;
A failure diagnosis system comprising: When the voltage acquisition unit prevents power generation in each of the plurality of solar cell modules, the voltage acquisition unit acquires the voltage information,
2. The failure according to claim 1, wherein the determination unit determines a solar cell module that is prevented from generating power as a failed solar cell module when the voltage information indicates a relatively low power generation voltage. Diagnostic system. A storage unit that stores the solar cell module and the voltage information that are prevented from generating power in association with each other;
The said determination part determines the solar cell module corresponding to the said voltage information which shows the relatively low power generation voltage memorize | stored in the said memory | storage part as a failed solar cell module. Fault diagnosis system. The voltage acquisition unit acquires the voltage information when power generation in each of the plurality of solar cell modules is prevented,
The said determination part determines the solar cell module in which the variation | change_quantity of the power generation voltage which the said voltage information shows relatively before and after power generation is prevented as a failed solar cell module. Fault diagnosis system. A storage unit that stores the solar cell module and the voltage information that are prevented from generating power in association with each other;
The determination unit is configured to determine, as a failed solar cell module, a solar cell module stored in the storage unit and having a relatively small amount of change in the generated voltage indicated by the voltage information before and after power generation is hindered. The fault diagnosis system according to claim 4, wherein The solar cell string is formed such that the plurality of solar cell modules are arranged in m rows (m is an integer of 2 or more) × n columns (n is an integer of 3 or more),
The voltage acquisition unit acquires the first voltage information as the voltage information when the power generation in each row of the plurality of solar cell modules is prevented, and when the power generation in each column of the plurality of solar cell modules is prevented. Obtaining second voltage information as the voltage information;
The determination unit includes a row of a solar cell module that has the smallest amount of change in the generated voltage indicated by the first voltage information before and after power generation is prevented, and a change in the generated voltage indicated by the second voltage information before and after power generation is prevented. The failure diagnosis system according to claim 1, wherein a solar cell module at a position where the row of solar cell modules having the smallest amount intersects is determined as a failed solar cell module. The row of the plurality of solar cell modules in which power generation is prevented and the first voltage information are stored in association with each other, and the column of the plurality of solar cell modules in which power generation is prevented and the second voltage information Are further stored in association with each other,
The determination unit determines a failed solar cell module based on the first voltage information and the second voltage information that are stored in the storage unit and have the smallest amount of change in generated voltage before and after power generation is prevented. The failure diagnosis system according to claim 6, wherein: A current monitoring unit for monitoring a current flowing in a solar cell string in which a plurality of solar cell modules are connected in series;
A current acquisition unit that acquires current information indicating a current flowing through the solar cell string monitored by the current monitoring unit when power generation in the plurality of solar cell modules is selectively prevented;
A determination unit that determines a failed solar cell module based on the current information acquired by the current acquisition unit;
A failure diagnosis system comprising: When the current acquisition unit prevents power generation in each of the plurality of solar cell modules, the current acquisition unit acquires the current information,
The failure diagnosis according to claim 8, wherein the determination unit determines a solar cell module in which power generation is prevented when the current information indicates a relatively high current as a failed solar cell module. system. A storage unit that stores the solar cell module and the current information that are prevented from generating power in association with each other,
The said determination part determines the solar cell module corresponding to the said current information which shows the relatively high electric current memorize | stored in the said memory | storage part as a failed solar cell module. Fault diagnosis system. The current acquisition unit acquires the current information while preventing power generation in each of the plurality of solar cell modules,
The failure according to claim 8, wherein the determination unit determines, as a failed solar cell module, a solar cell module in which a change amount of a current indicated by the current information is relatively small before and after power generation is hindered. Diagnostic system. A storage unit that stores the solar cell module and the current information that are prevented from generating power in association with each other,
The determination unit determines, as a failed solar cell module, a solar cell module stored in the storage unit and having a relatively small amount of change in current indicated by the current information before and after power generation is prevented. The fault diagnosis system according to claim 11. The solar cell string is formed such that the plurality of solar cell modules are arranged in m rows (m is an integer of 2 or more) × n columns (n is an integer of 3 or more),
The current acquisition unit acquires the first current information as the current information when the power generation in each row of the plurality of solar cell modules is prevented, and the power acquisition unit prevents the power generation in each column of the plurality of solar cell modules. Obtaining second current information as the current information;
The determination unit includes a row of solar cell modules in which the change amount of current indicated by the first current information is the smallest before and after power generation is prevented, and a change amount of current indicated by the second current information before and after generation is prevented. The fault diagnosis system according to claim 8, wherein a solar cell module at a position where the row of the smallest solar cell modules intersects is determined as a faulty solar cell module. A row of the plurality of solar cell modules in which power generation is prevented and the first current information are stored in association with each other, and a row of the plurality of solar cell modules in which power generation is prevented and the second current information, Are further stored in association with each other,
The determination unit determines a failed solar cell module based on the first current information and the second current information, which are stored in the storage unit and have the smallest current change amount before and after power generation is prevented. The failure diagnosis system according to claim 13. A shielding unit that shields a solar light receiving surface of the plurality of solar cell modules, so that power generation in each of the plurality of solar cell modules is hindered;
The fault diagnosis system according to any one of claims 2 to 5 and claim 9 to claim 12, further comprising: A first shielding portion that shields a solar light receiving surface of the plurality of solar cell modules so that power generation in each row of the plurality of solar cell modules is prevented;
A second shielding portion that shields a solar light receiving surface of the plurality of solar cell modules so that power generation in each row of the plurality of solar cell modules is hindered;
The fault diagnosis system according to any one of claims 6, 7, 13, and 14, further comprising: Each of the plurality of solar cell modules is
A plurality of solar cells connected in series and folded in units of a predetermined number;
The bypass diode which conduct | electrically_connects when the electric power generation of either photovoltaic cell is interrupted among these photovoltaic cells, The Claim 1 thru | or 16 characterized by the above-mentioned. Fault diagnosis system. Monitoring the power generation voltage of a predetermined solar cell module in a solar cell string in which a plurality of solar cell modules are connected in series;
When selectively preventing power generation in the plurality of solar cell modules, obtain voltage information indicating the power generation voltage of the predetermined solar cell module monitored,
A failure diagnosis method characterized by determining a failed solar cell module based on the acquired voltage information. Monitor the current flowing in the solar cell string in which multiple solar cell modules are connected in series,
When selectively preventing power generation in the plurality of solar cell modules, obtaining current information indicating a current of the monitored solar cell string;
A fault diagnosis method, wherein a faulty solar cell module is determined based on the acquired current information.